Comparative Study of Pathophysiological Mechanisms and Bronchial Response in Occupational Asthma to Wheat Flour and Quaternary Ammonium Compounds During Standardized Bronchial Provocation Tests

University Hospital, Strasbourg, France35 enrolled

Overview

Occupational asthma (OA) caused by high molecular weight (HMW) substances have been shown to induce predominantly an eosinophilic inflammation. In contrast, OA caused by low molecular weight (LMW) substances results in a neutrophilic inflammation. In addition, data regarding phenotype of lymphocytes in OA caused by HMW and LMW substances are scarce. The use of a new equipment will allow the realization of specific standardized bronchial challenges (BC) to occupational agents. Thus, we propose to study in more detail the cellular mechanisms involved during BC to HMW and LMW occupational agents in a double-blind placebo controlled study.

Study Type

INTERVENTIONAL

Allocation

RANDOMIZED

Purpose

OTHER

Masking

TRIPLE

Enrollment

Conditions

Occupational Asthma

Interventions

At Visit 1: Patients are selected and they will receive a metacholine challenge test during and outside of work. After randomization, patients undergo a standardized bronchial challenge test (SCL SCL • • GenaSOL ™ GenaSIC ™) to either an wheat flour allergen extract or didecyldimethylammonium chloride or placebo. Each bronchial challenge test is followed by blood sampling at different time points and induced sputum. The immediate bronchial response and late bronchial response will be recorded.

Eligibility

Sex: ALLMin age: 18 YearsMax age: 50 Years

Medical Language ↔ Plain English

Inclusion Criteria: For patients with occupational asthma to wheat flour: * Clinical history, * A positive skin test to wheat flour and / or specific IgE to wheat flour For patients with occupational asthma to quaternary ammonium compounds: -Clinical history, For two types of asthma: * Patients must have a worsening of bronchial hyperreactivity during work compared to a rest period assessed by a metacholine challenge * FEV before challenge (nonspecific and specific) must be\> 70%. Exclusion Criteria: Asthmas: * no occupational asthma: * secondary to clinically relevant sensitization to an allergen domestic * aggravated at work.

Outcomes

Primary Outcomes

Assessment of cellular inflammation in peripheral blood and induced sputum

Before and after bronchial challenge: assessment of cellular inflammation in peripheral blood and induced sputum, exhaled NO; assessment of peripheral T lymphocyte phenotype.

Time frame: 33 months